Photographic products and processes



E. M.-IDELSON ETAL 3,307,947

PHOTOGRAPHIC PRODUCTS AND PROCESSES March 7, 1967 Filed Deg. 16, 1964 ISUPPORT IMAGE-RECEIVING- LAYER I RUPTURABLE CONTAINER HOLDING APROCESSING COMPOSITION SILVER HALIDE EMULSION LAYER AND ASSOCIATEDTEMPORARILY SHIFTED DYE DEVELOPER iogIz FIG. I

I/SUPPORT /IMAGE-RECEIVING LAYER LAYER OF PROCESSING COMPOSITIONBLUE-SENSITIVE EMULSION AND I ASSOCIATED YELLOW DYE DEVELOPERGREEN-SENSITIVE EMULSION AND ASSOCIATED TEMPORARILY SHIFTED MAGENTA DYEDEVELOPER RED-SENSITIVE EMULSION AND ASSOCIATED CYAN DYE DEVELOPERSUPPORT FIG. 2

INVENTORi W 7/ Jade/WY WAVELENGTH IN MILLIMICRONS FIG. 3

L147 BY $10M MML 7WAAQ" TTORNEYS United States Patent 3,307,947PHOTOGRAPHIC PRODUCTS AND PROCESSES Elbert M. Idelson, Newton, andHoward G. Rogers,

Weston, Mass., assignors to Polaroid Corporation, Cambridge, Mass., acorporation of Delaware Filed Dec. 16, 1964, Ser. No. 418,628 14 Claims.(Cl. 96-29) This application is in part a continuation of our copendingUS. application Serial No. 788,892, filed January 26, 1959, nowabandoned.

This invention relates to photography and, more particularly, to animprovement in photographic diffusiontransfer reversal processes forobtaining color images.

The copending US. application of Howard G. Rogers, Serial No. 789,080,filed January 26, 1959, now abandoned, discloses and claimsdiffusion-transfer reversal processes employing a photosensitiveelement, comprising not less than one silver halide emulsion havingassociated therewith not less than one image-forming component having atemporarily shifted light-absorption spectrum. The photosensitiveelement may be exposed to a predetermined actinic energy pattern and theresultant latent silver halide image or images formed thereby developedin said emulsion or emulsions to effect, as a result of development,v

immobilization of the respective associated image-forming components inthe exposed areas of said photosensitive element. An imagewisedistribution of mobile imageforming components is thus provided in theunexposed areas of said photosensitive element which may be, at least inpart, transferred by imbibition from the unexposed areas to a superposedimage-receiving layer. A nonreversible restoration of at least a portionof the temporarily shifted image-forming components to their originalspectral absorption characteristics is effected, at some stagesubsequent to exposure, so as to impart to the image-receiving layer areversed positive dye image of the latent image exhibiting the desiredspectral absorption characteristics.

It is a primary object of the present invention to provide novelphotographic diffusiondransfer reversal processes and novel products forultization therein.

Another object, of the present invention is to provide novelphotosensitive elements, comprising not less than one silver halideemulsion and not less than one dye developer, possessing increasedemulsion speed and improved exposure control.

A further object of the present invention is to provide novelphotographic compounds, processes'and products for obtaining colorimages by diffusion-transfer reversal processes, wherein the lightabsorption characteristics of the dye developers utilized to providesaid color images are temporarily shifted so that said dye developersabsorb actinic energy at wave lengths substantially shorter duringexposure than the wave lengths of the respective dye developersultimately desired.

A still further object of the present invention is to provide novelphotographic compounds, processes and products for obtaining colorimages by diffusion-transfer reversal processes, wherein the lightabsorption characteristics of the dye developers utilized to providesaid color images are temporarily shifted so that said dye developersabsorb actinic energy at wave lengths substantially shorter duringexposure than the wave lengths of which the dye developers associatedsilver halide emulsion is sensitized.

A still further object of the present invention is to provide novelphotographic compounds, processes and products for obtaining multicolortransfer images, using integral multilayer photosensitive elements,whereby unwanted absorption, that is, absorption at the wave lengths ofemulsion sensitization, is avoided.

A still further object of the present invention is to 3,307,947 PatentedMar. 7 1967 provide novel photographic processes whereby temporarilyshifted dye developers, that is, dye developers the spectral absorptionbands of which have been temporarily shifted to lower wave lengths priorto exposure of a photosensi' tive element containing said dyedevelopers, may be restored to their original spectral absorptioncharacteristics subsequent to exposure of said photosensitive element.

A still further object of the present invention is to provide dyedevelopers, the spectral absorption characteristics of which aremodified to effect a temporary hypsochromic shift in the wave lengthsabsorbed during exposure of an associated photosensitive emulsion andwhich, subsequent to said exposure, may be restored to their originalabsorption characteristics.

Other objects of the invention will in part be obvious and will in partappear hereinafter.

I The invention accordingly comprises the several steps and the relationand order of one or more of such steps with respect to each of theothers, and the product possessingthe features, properties and therelation of elements which are exemplified in the following detaileddisclosure,

and the scope of the application of which will be indicated in theclaims.

For a fuller understanding ofthe nature and objects of the invention,reference should be had to the following detailed description taken inconnection with the accompanying drawings wherein:

FIGURE 1 is a diagrammatic cross-sectional view of one embodiment of aphotographic product for use in obtaining monochromatic images inaccordance with this invention and comprising a photosensitive element,an image-receiving element and a rupturable container holding aprocessing composition;

FIG. 2 is a diagrammatic cross-sectional view of one embodiment of thisinvention, for use in obtaining multicolor images, during processing andcomprising a multilayer photosensitive element, an image-receivingelement and a processing composition; and

tion characteristics of a dye developer of the present inventionspreferred class including the temporarily shifted absorption curve ofthe modified dye developer superposed upon the absorption curve of thereconstituted, original dye developer and the corresponding curves of aclosely related auxochromophoric system set forth for the purpose ofproviding comparative data.

The expression temporarily shifted dye developer as used herein isintended to signify a dye developer which has been modified chemicallyso that its spectral absorption bands have been relocated atsubstantially shorter wave lengths, that is, a hypsochromic shift of theabsorption spectrum, for at least the time interval necessary toaccomplish photoexposure of a photosensitive silver halide emulsionassociated therewith, and which dye developer is subject to restorationof the dye developers original absorption characteristics upon simplechemical treatment, such as, for example, hydrolysis, me'thanolysis,ammonolysis, etc.

It has been proposed, in the copending US. application of Howard G.Rogers, Serial No. 748,421, filed July 14, 1958 (now US Patent No.2,983,606, issued May 9, 1961), to form color images bydiffusion-transfer reversal processes utilizing dye developers. Inprocesses of this type, a photosensitive element containing a dyedeveloper and a silver halide emulsion is exposed and wetted by a liquidprocessing composition,'for example, by immersion, coating, spraying,flowing, etc., in the dark, and the exposed photosensitive element issuperposed prior to, during, or after wetting, on a sheetlike supportelement which may be utilized as an imagereceiving element. In apreferred embodiment, the liquid processing composition is applied tothe photosensitive element in a substantially uniform layer as thephotosensitive element is brought into superposed relationship with theimage-receiving layer. The liquid processing composition permeates theemulsion to initiate development of the latent image contained therein.The dye developer is immobilized or precipitated in exposed areas as aconsequence of the development of the latent image. This immobilizationis apparently, at least in part, due to a change in the solubilitycharacteristics of the dye developer upon oxidation and especially asregards its solubility in alkaline solutions. It may also be due in partto a tanning effect on the emulsion by oxidized developing agent, and inpart to a localized exhaustion of alkali as a result of development. Inunexposed and partially exposed areas of the emulsion, the dye developeris unreacted and diifusible and thus provides an imagewise distributionof unoxidized dye developer dissolved in the liquid processingcomposition, as a function of the point-to-point degree of exposure ofthe silver halide emulsion. At least part of this imagewise distributionof unoxidized dye developer is transferred, by imbibition, to asuperposed image-receiving layer or element, said transfer substantiallyexcluding dye developer. Under certain conditions, the layer of liquidprocessing composition may be utilized as the image-receiving layer. Theimage-receiving element receives a depthwise diffusion, from thedeveloped emulsion, of unoxidized dye developer without appreciablydisturbing the imagewise distribution thereof to provide the reversed orpositive color image of the developed image. The image-receiving elementmay contain agents adapted to mordant or otherwise fix the diffused,unoxidized dye developer. If the color of the transferred dye developeris affected by changes in the pH of the image-receiving element, this pHmay be adjusted in accordance with well-known techniques to provide a pHaffording the desired color. The desired positive image is revealed bystripping the image-receiving layer from the photosensitive element atthe end of a suitable imbibition period.

The dye developers, as noted above, are compounds which contain, in thesame molecule, both the chromophoric system of a dye and also a silverhalide developing function. By a silver halide developing function ismeant a grouping adapted to develop exposed silver halide. A preferredsilver halide development function is a hydroquinonyl group. Othersuitable developing functions include ortho-dihydroxyphenyl and orthoandpara-amino substituted hydroxyphenyl groups. In general, the developmentfunction includes a benzenoid developing function, that is, an aromaticdeveloping group which forms quinonoid or quinone substances whenoxidized.

The preferred dye developers possess the characteristics of relativelyhigh absorption of actinic radiation over a desired segment of thespectral range as well as substantially no absorption over the remainingportion of the spectrum. For example, in a diffusion-transfer reversalprocess for three-color subtractive photography, the preferred dyedevelopers utilized should comprise, respectively, a yellow, a magenta,and a cyan dye developer, each of said dye developers having a hightransmittance over approximately two-thirds of the visible sgecgrum, anda high absorption in the remaining onet ir Where such dye developers areinitially colored and situated in an appropriately sensitized emulsionlayer, that is, an emulsion layer sensitized to areas of the visiblespectrum coinciding with the absorption maximum of the respectiveassociated dye developers, it is obvious that the amount of actinicenergy necessary to accomplish suitable excitation of the sensitizedsilver halide crystals contained within said emulsion is substantiallyincreased The resultant effect of the dye developers absorption of asubstantial proportion of the actinic energy available for silver halidecrystal excitation is necessarily a substantial decrease in the relativespeed of the associated photosensitive emulsion.

As previously stated, in multicolor photographic processes, therespective preferred dye developers should theoretically absorb actinicradiation over a selected portion of the spectral range equal to thecolor absorption desired and further should exert no influence on and/or absorption over the remaining portions of the spectrum. Thus, eachdye developer associated emulsion layer unit, comprising a multilayerphotosensitive element for use in obtaining multicolor images, shouldtheoretically absorb spectral radiation on a predelineated area of thespectral range. Therefore, in an integral multilayer photosensitiveelement, such as illustrated in FIG. 2, which comprises threeappropriately sensitized silver ;halide emulsions having associatedtherewith, respectively, a yellow, a magenta and a cyan dye developer,the preferred yellow dye developer should be one with relatively highabsorption in the blue area of the spectrum and thus would affect orcontrol only the amount of blue light passing through said dye developerbut would have substantially little, if any, influence on the passage ofred or green light. The magenta dye developer should be one withrelatively high absorption in the green area of the spectrum and thuswould aflect and/or control only the amount of green light passingthrough said dye developer but would have substantially little, if any,influence on the passage of red or blue light. The cyan dye developershould be one with relatively high absorption in the red area of thespectrum and thus would atfect or control only the amount of red lightpassing through said dye developer but would have substantially little,if any, influence on the passage of blue or green light.

Therefore, in an integral multilayer photosensitive element of the typepreviously described, upon exposure to actinic radiation comprising thevisible spectrum, said radiation preferably traversing through ablue-sensitive emulsion perpendicular to the plane of saidphotosensitive element, the respective yellow dye developer ordevelopers should theoretically absorb only the blue portion of thespectrum, thus allowing undiminished red and green wave lengths tocontact a subsequent greensensitive magenta dye developer containingsilver halide emulsion. The magenta dye developer, in turn, shouldtheoretically absorb only the green wave lengths of the spectrum andthus allow the red wave lengths to contact, with undiminished energy, asubsequent red-sensitive cyan dye developer containing silver halideemulsion. Many yellow, magenta and cyan dye developers exhibitsubstantial spectral absorption in areas of the spectrum other thantheir preferred theoretical areas.

The unavailability of dye developers with desired absorptioncharacteristics, that is, over one-third of the spectrum, and desiredtransmission characteristics, that is, over two-thirds of the spectrum,necessitates formulating a method of preand/ or post-correcting of eachemulsion layer to avoid the loss of a substantial amount of actinicenergy upon exposure due to the undesirable absorption of the dyedeveloper associated emulsion layers through which the actinic radiationmust traverse in order to expose subsequent photosensitive emulsionlayers.

It has been discovered that the necessity of correcting or compensatingfor the aforementioned undesirable absorption, that is, internalabsorption within the respective emulsion layer decreasing the speed ofsaid emulsion, as well as decreasing the actinic radiation transmittedthrough said emulsion, may be substantially obviated by effectingtemporarily, that is, at least for the duration of exposure of aphotosensitive element, a hy-psochromic shift of the absorptioncharacteristics of the respective dye developers such that theabsorption of said dye developers is rendered negligible andtransmission of the preferred spectral rays. of light approximates themagnitude desired.

Dispersion of an associated dye developer in the photo sensitiveemulsion generally results in a substantial loss of the sensitivity ofthe emulsion due to the dye developer absorbing actinic energy in thecorresponding region of maximum emulsion sensitivity. This is apparentlydue to the fact that photographic dye developers associated with aphotosensitive silver halide emulsion generally possess a color, thatis, a spectral absorption curve, which is substantially the same as thatof the light, that is, the region of the spectrum, which the sensitizedemulsion is intended to record. In such instances, the dye developer hasits light absorption maximum, that is, k at a wave length within themaximum sensitivity of the photosensitive emulsion with which it isassociated.

A hypsochromic shift of the light absorption spectrum of the respectivedye developer is preferred since the absorption bands of the dye falloff more sharply on the long wave length side of the A A hypsochromicshift of the A approximating 100 mp. substantially avoids absorption ofspectral energy by the respective dye developer in the spectral regionto which the associated emulsion is sensitized. However, it must benoted that a hypsochromic shift of the A approximating 20 to 30 m maysubstantially obviate the filtering effect of the respective dyedevelopers absorption on photosensitive emulsions in a rearward positionrequired by the conventional arrangement of integral multilayerphotosensitive elements.

It has now been discovered that the aforementioned temporary shift ofthe dye developers absorption characteristics may be attained by theutilization of monoand disazo dye developers wherein the bathochromiceffects of auxochromic hydroxy or amino substituted radicals substitutedat specific positions in relation to the azo configuration, have beentemporarily reduced by appropriately isolating said radicals frominteraction with the azo chromophore.

From the standpoint of the color of dyes, an auxochrome is best definedas a substituent atom or group which increases the intensity (6) of theabsorption of light due to a chromophore. An auxochrome may also shiftthe main absorption band (A to a longer wave length, just was a secondchromophore conjugated with the first increases the e in addition toshifting it to a longer A It must be noted, however, that a givenauxochrome may increase the 6 only for certain chromophores, and onlywhen it is situated in a suitable position with reference to saidchromophore, to thus form an auxochromophoric system. In anauxochromophoric system, it is believed that the absorption of lightresults from the electronic interaction between auxochromes andchromophores by which the contribution of highly conjugated andpolarized structures to the resonance of the dye molecule is increased.

Auxochromic hydroxyl and amino groups play a vital role in influencingthe absorption characteristics of the azo dye developers of thisinvention by reason of electronic interaction between the azochromophore and the respective hydroxyl or amino group. The position ofthe respective substituent in relation to the azo linkage largelydetermines the auxo-chromic effect; since resonance effects areinoperative in the meta position, auxochromic substituents are mainlyeffective in the ortho and para positions with respect to the azochromophore.

Specifically, it has now been discovered that the previouslycharacterized advantages achieved by the utilization of temporarilyshifted dye developers, in photographic systems, may be obtained by theemployment of dye developers wherein the bathochromic effects ofspecified auxochrome components, of the selected auxochromophoricsystems, may be temporarily reduced by interruption of the electronicinteraction between the respective auxochromes and chromophores and,more specifically, by interruption of the last-mentioned electronicinteraction between auxochromic hydoxyl or amino groups substituted inortho and/or para position with respect to a chromophoric azo linkage,effected by any suitable technique, but, most preferably, by means ofeffecting temporary acylation of the respective auxochrome substituentor substituents. Restoration of the original auxochromophoric system maybe then readily secured by hydrolysis of the introduced acyl group suchas, for example, hydrolysis of such acyl group by means of contact withan aqueous alkaline photographic processing composition.

While the last-mentioned acylation, of the selected auxochromicsubstituent, does accomplish a hypsochromic shift in the spectralabsorption characteristics of the selected auxochromophoric system,Where the selected auxochromic substituent comprises an amino groupsubstituted in ortho or para position with relation to a chromophoricazo linkage and/or a hydroxyl group substituted in para position to suchan azo linkage, it has quite unexpectedly been found that acylation ofan auxochromic hydroxyl group substituted in ortho position withrelation to a chromophoric azo linkage provides a hypsochromic shift ofsuch extended magnitude as to be totally unexpected in view of, andunrelated in comparison with, the magnitude of hypsochromic shiftprovided the previously identified components.

As stated hereinbefore, a temporary hypsochromic shift of the dyedevelopers A at least for the period during which exposure of aphotographic film unit retaining same is accomplished, constituting amagnitude of 20 to 30 m may be sufficient to substantially avoid afiltering effect, in the transmission of actinic energy to a rearwardlypositioned photosensitive emulsion, in many desired instances. Incertain instances, therefore, acylation of a selected auxochromic aminogroup substituted ortho or para to a chromophoric azo linkage or, forexample, alternatively, acylation of an auxochromic hydroxyl groupsubstituted para to a chromophoric azo linkage may be sufficient toprovide the desired radiation absorptive characteristics to a givenphotographic film unit. In many instances, however, the maximummagnitude of such shift is considerably less than that required toprovide the optimum radiation absorbing characteristics to the filmunit. 'In such circumstances, it is necessary that acylation of anauxochromic hydroxyl group substituted in ortho position with respect toa chromophoric azo linkage, in accordance with the present disclosure,must be employed to provide the required photographic opticalproperties.

In specific illustration of the respective magnitude of the hypsochromicshift obtained by the last-mentioned procedure, and comparison with theprocedure detailed immediately preceding same, reference may be made toFIG. 3 of the drawing wherein there is graphically illustrated thereduction of the bathochromic effect of a preferred auxochromophoric dyedeveloper system, induced by temporary acylation of an auxochromichydroxyl group substituted in ortho position with respect to achromophoric azo configuration, and which is further graphicallycompared with the reduction in the bathochromic effect of a comparativeauxochromophoric dye system, induced by the temporary acylation of anauxochromic hydroxyl group substituted in para position with respect toa chromophoric azo configuration. The graphic illustrations Curve A setsforth the spectral absorption curve of a preferred auxochromophoric dyedeveloper system, that is, 2(p-[fl-(hydroquinonyl)-ethyll-phenylazo)-4-methoxyl-naphthol, exhibitinga Amax. at 529 mg, in acetone, e=19,800, and the graphic illustrationsCurve B sets forth the spectral absorption curve of the last-mentioneddye developer specifically acylated in accordance with the instantdisclosure, that is 1-acetoxy-2-(p-[fl-(hydroquinonyl -ethyl] -phenylazo-4-methoxy-naphthalene, exhibiting a kmax, at 390 m in acetone, 6=6,700,thus illustrating, by superpositioning of the respective curves, theoptical effects of the temporary modification of a preferred azo dyedeveloper according to the instant disclosure.

The graphic illustrations Curve C sets forth the spectral absorptioncurve of the auxochromophoric dye systemv (4-phenylazo-l-naphthol),exhibiting a kmax, at 410 m l, in methyl Cellosolve, e=16,200, and thegraphic illustrations Curve D sets forth the spectral absorption curveof the last-mentioned dye system specifically acylated in accordancewith the instant disclosure, that is, l-acetoxy-4-phenylazo-naphthalene, exhibiting a A at 374 my, in methyl Cellosolve,e:11,400, thus illustrating, by superpositioning of the respectivecurves, the optical elfects of a temporary modification of a comparativedye system according to the disclosure detailed herein and comparison ofthe magnitude of the modification achieved employing the designatedacylation of an auxochromic hydroxy group positioned in pararelationship to a chromophoric azo group, with the magnitude of themodification obtained by the specified acylation of an auxochromichydroxyl group in ortho position to a chromophoric azo group. It willthus be readily appreciated that the hypsochromic shift achieved by thepreferred procedure of the instant disclosure, illustrated in FIG. 3 ofthe drawing, comprises a shift in the hmax, approximately 139 m whereasthe corresponding hypsochromic shift in the k obtained in the exampledetailed in FIG. 3 for comparative purposes, approximates 36 m It shouldalso be noted that repetition of the above procedure specificallycomparing acylation of the above-identified auxochromic amino groupswith the preferred system of the present disclosure will confirm theunexpected magnitude of the hy-psochromic shift achieved by the instantdisclosures preferred procedure.

The preferred group of dye developers, the spectral absorption curve ofwhich may be subjected to a temporary hypsochromic shift by isolation ofan appropriate auxochromic substituent, comprises monoand disazo dyedevelopers characterized in that they contain an auxochromic hydroxylgroup substituted on an aryl nucleus in ortho or ortho,ortho positionsto one or both azo lin-kages, that is, monoand disazo dye developerscharacterized in that said dye developers contain not less than one andnot more than two groups selected from the groups represented by theformulae:

(2) OH OH OH OH wherein a is one or two; 17 is one or two; X is ap-dihydroxyphenyl or an o-dihydroxyphenyl group and the halogen andalkyl substituted derivatives thereof; each Y represents thenon-metallic atoms necessary to complete an aryl nucleus, preferably abenzene or naphthalene nucleus, which aryl nuclei may be the same ordifferent; and Z represents the residue of an azo coupler.

As examples of ortho-hydroxy and/or ortho,ortho'- dihydroxy substitutedmonoand disazo dye developers preferred for use in the practice of thepresent invention, mention may be made of the following:

2- (4- [4- (2",5 -dihydroxyphenethyl) phenylazo] naphthalene azo-4-methoxyl-naphthol p-( l-hydroXy-4methoxy-2-nap hthalene azo)-phenethyl catcheol 2- pfl- (hydroquinonyl -ethyl] -phenylazo)-4-methoxyl-naphthol 2- (p- B- (hydro quinonyl) -ethyl] -phenylazo-4-n-propoxyl-naphthol the preparations of which are disclosed in thecopending U.S. application of Elkan R. Blout, Milton Green, and HowardG. Rogers, Serial No. 612,045, filed September 25, 1956, abandoned andreplaced by Serial No. 144,816, filed October 18, 1961 (now U.S. PatentNo. 3,134,672, issued May 26, 1964);

2-( 2,5 '-dimethoxy-4'- p- 2",5 "-dihydroxyphenyl) phenylazo]-phenylazo)-4-methoxy-1-naphthol the preparation of which is disclosed in thecopending U.S. application of Helen P. Husek and Myron S. Simon, SerialNo. 612,054, filed September 25, 1956, now abandoned and replaced bySerial No. 197,283, filed May 24, 1962 (now U.S. Patent No. 3,236,645,issued Feb. 22, 1966), and Serial No. 197,259, filed May 24, 1962 (nowU.S. Patent No. 3,134,763, issued May 26, 1954);

2-(2',5'-dimethoxy-4'- [p-(2",5-d ihydroxyphenethyl)- phenylazo]-phenylazo) -4-methoxy-1-naphthol the preparation of which is disclosedin the copending U.S. application of Helen P. Husek, Serial No. 612,055,filed September 25, 1956, now abandoned and replaced by Serial No.192,355, filed May 4, 1962 (now U.S. Patent No. 3,236,643, issued Feb.22, 1966), and Serial No. 192,354, filed May 4, 1962 (now U.S. PatentNo. 3,134,762, issued May 26, 1954);

2- ('p- [4-methyl-2',5 '-dihydroxyphenylthioethyl] phenylazo-4-methoxy-naphthol the preparation of which is disclosed in thecopending U.S. application of Milton Green and Howard G. Rogers, SerialNo. 663,905, filed June 6, 1957, now abandoned and replaced by SerialNo. 193,326, filed May 8, 1962 (now U.S. Patent No. 3,222,169, issuedDec. 7, 1965);

2- (p- 2,5 '-dihydroxyphenoxy] -phenylazo -4-methoxyl-naphthol thepreparation of which is disclosed in the copending U.S. application ofMilton Green, Serial No. 680,403, filed August 26, 1957, now abandoned;

2-(p- [hydroquinonylsulfonyl] -phenylazo) -4-methoxyl-naphthol thepreparation of which is disclosed in the copending U.S. application ofMilton Green, Serial No. 680,434, filed August 26, 1957, now abandonedand replaced by Serial No. 230,287, filed October 12, 1962 (now U.S.Patent No. 3,230,086, issued Jan. 18, 1966-);

2-(2,5 -dimethoxy-3 [2",- (2",5"'-dihydroxybenzoyl) ethyl] -phenylazo)-4-methoxy-1-naphthol the preparation of which is disclosed in thecopending U.S. application of Elkan R. Blout, Milton Green, Howard G.Rogers, and Myron S. Simon, Serial No. 685,081, filed September 20,1957, now abandoned and replaced by Serial No. 222,702, filed September10, 1962 (now U. 5. Patent No. 3,208,991), and Serial No. 222,656, filedSeptember 10, 1962 (now U.S. Patent No. 3,143,565);

2-(4'- [p-(hydroquinonyl) -phenylcarboxamido] -phenylazo)-4-me-thoxy-1-naphthol 9. the preparation of which is disclosed in thecopending US. application of Milton Green, Serial No. 703,515, filedDecember 18, 1957, now abandoned;

4,4-bis- (4- [2,5 '-dihydroxyphenethyl] -phenylsulfamyl)-1-hydroxy-l,2-azonaphthalene 4- (4- [2",5 -dihydroxyphenethyl]-N-methyl-phenylsulfamyl) -2- (2',5 '-dimethoxyphenylazo) -l -naphtholthe preparations of which are disclosed in the copending US. applicationof Elkan R. Blout, Milton Green, Ho ard G. Rogers, and Robert B.Woodward, Serial No. 707,109, filed January 6, 1958, now abandoned;

2- (4'- [4- (2,'5 -dihydroxyp'henethyl -phenylcarbamyl] -phenylazo)-4-methoxy-1-naphthol the preparation of which is disclosed in thecopending US. application of Milton Green and Howard G. Rogers, SerialNo. 748,145, filed July 14, 1958, now abandoned and replaced by SerialNo. 190,804, filed April 27, 1962 (now US. Patent No. 3,186,982, issuedJune 1, 1965); and

1- (4- [2,5 -dihydroxyphenethyl] -2'-hydroxy-phenylazo) -2-naphthol thepreparation of which is disclosed in the copending US. application ofMilton Green and Myron S. Simon, Serial No. 788,893, filed January 26,1959, now abandoned.

In compounds comprising the last-mentioned class of dye developers, theauxochrornic hydroxyl group may be selectively isolated from interactionwith the azo chromophore by acylation of said hydroxyl group accordingto the following procedure, in order to provide the preferred dyedevelopers for use in the practice of the present invention. These dyedevelopers comprise novel monoand disazo dye developers characterized inthat said dye developers contain not less than one and not more than twogroups of the formula:

ortho to at least one azo group, and not more than one of said groups isortho to the same nitrogen atom of said azo group; and which dyes mayalso be characterized in that they contain not less than one and notmore than two groups selected from the groups represented by theformulae:

(7) fl I wherein each R is an alkyl group, preferably a lower alkylgroup of from 1 to carbon atoms such as methyl, ethyl, propyl, butyl,etc.; and said dye developers being further characterized in that theycontain not less than one and preferably not more than two groupsselected from the group consisting of a p-dihydroxyphenyl and ano-dihydroxyphenyl group.

It has been discovered that compounds within the aforementioned formulaemay be prepared by oxidizing to the quinone the p-dihydroxyphenyl oro-dihydroxyphenyl groups or derivatives thereof of monoor disazo dyescharacterized in that said dyes contain not less than one and not morethan two ortho-hydroxyazo and/or ortho, ortho'-dihydroxyazoconfigurations and said dyes being further characterized in that theycontain not less than one and not more than two groups selected from thegroup consisting of p-dihydroxyphenyl and o-dihydroxyphenyl groups andthe halogen and alkyl substituted derivatives thereof, said oxidatitonbeing accomplished, for example, with an oxidizing agent such asbenzoquinone, chloranil, etc.; acylating the hydroxyl groups substitutedortho and/ or ortho to one or more azo groups by reacting the oxidationproduct with an acylating agent, preferably an enol ester, especially anenol ester of the formula:

wherein R and R each may be the same or different and are hydrogen or analkyl group, such as CH C H etc.; R is hydrogen, an alkyl group, such asCH nC H n-C H etc., an alkenyl group, such as CH3 CH D=C H- or an arylgroup, such as phenyl; and R is an alkyl group; said acylationpreferably being accomplished either utilizing the acylating compound asthe solvent medium or in an inert solvent such as methylene chloride,ethyl acetate, etc., in the presence of a suitable catalyst such as astrong inorganic acid, for example, concentrated perchloric, sulfuric,etc., acids; and regenerating the p-dihydroxyphenyl or o-dihydroxyphenylgroups or derivatives thereof by reduction, said reduction beingaccomplished, for example, with a reducing agent such asxylohydroquinone or hydrogen in the presence of a suitable catalyst suchas a palladium/charcoal catalyst.

It is contemplated within the scope of this invention that, wheredesirable, the dyes may contain one or more hydroxyl groups substitutedthereon in addition to those previously mentioned. Under suchconditions, the acylation action may be continued until substantiallycomplete acylation is attained, that is, acylation of each free hydroxylgroup of the respective dye molecules.

As illustrative examples of the preferred enol ester acylating agentsdeemed suitable for utilization in the practice of this invention,mention may be made of:

l-propen-Z-ol acetate,

2-buten-2-ol acetate, 4-methyl-1,3-pentadiene-2-ol acetate,l-phenylethanol acetate, 4-methyl-2-penten-olacetate, 2-hepten-2-olacetate,

2-octen-2-ol acetate, 2,6-dimethyl-4-hepten-4-ol acetate, vinyl acetate,

1-hexen-2-ol acetate,

l-hepten-Z-ol acetate, l-hexen-2-ol-chloroacetate, etc.

Additional useful azo dye developers, that is, azo dye developerswherein amino groups are substituted ortho or para or wherein hydroxylgroups are substituted para to an azo linkage, may be suitably acylatedby reaction with an appropriate acid chloride or anhydride, that is,acylating the respective hydroxyl or amino auxochromic group in thepresence of or subsequent to effecting temporary protection of thesilver halide developer imparting radicals of the aforementioned dyedevelopers benzenoid.

developing group or groups.

As additional examples of acylating agents which may be employed insynthesizing the previously-detailed acylated dye developers, mentionmay be made of bromoacetyl bromide; chloroacetyl chloride; acetylchloride; phenylacetyl chloride; acetyl bromide; n-butyryl chloride;propionyl chloride; iso-valeryl chloride; n-valeryl chloride;a-bromopropionyl bromide; dichloroacetyl chloride; cinnamoyl chloride;hexanoyl chloride; n-heptoyl chloride; hydrocinnamoyl chloride;iso-butyryl chloride; 4- methyl-n-valeryl chloride; crotonyl chloride;a-phenoxypropionyl chloride; phenoxyacetyl chloride; octanoyl chloride;propionyl bromide; u-ethyhn-butyryl chloride; iso-butyryl bromide;n-valeryl bromide; iso-valeryl bromide; DL-Z-methyl-n-butyryl chloride;wbromo-iso-butyryl bromide; and the corresponding anhydrides, formatesand chloroformates.

It will be recognized, from the preceding discussion, that the alkylgroup represented by the term R may comprise a substituted alkyl, oraliphatic, group which may be saturated or unsaturated, in accordancewith the specific acylating agent optionally chosen to conform with thedesires of the operator.

With specific regard to the p-dihydroxyphenyl and o-dihydroxyl groups,or radicals, the remaining hydrogen atoms in the phenyl ring system maybe suitably substituted by hydroxyl groups, amino groups, alkyl groups,or halogen atoms such as chloride and bromide atoms, and the like, whichdo not interfere with the photographic silver halide developingcharacteristics of the specified dihydroxyphenyl ring system.

In accordance with the present invention, it is contemplated to utilizea temporarily shifted dye developer and, specifically, a dye developerof the preferred class detailed hereinbefore, in both monochromatic andmulticolor diffusion-transfer reversal processes. It is contem lated touse at least one of the dye developers employed in multicolordiffusion-transfer reversal processes in the form of a temporarilyshifted dye developer. Significant improvements may result from the useof even one temporarily shifted dye developer in a multicolor process.It is also contemplated to employ a plurality of temporarily shifted dyedevelopers containing varying modifying groups to effect temporary shiftof the respective dye developers spectral characteristics.

The novel temporarily shifted dye developers of the present inventionalso find extensive application in subtractive color correctionprocesses, such as the integral masking procedures utilizing temporarilyshifted dye developers disclosed and claimed in the aforementioned copending US. application, Serial No. 789,080.

FIG. 1 of the accompanying drawing illustrates one method of processinga silver halide emulsion to obtain a monochromatic transfer image inaccordance with this invention. A photosensitive element 22 comprises asupport 20, a layer 16 containing a temporarily shifted dye developer,and a silver halide emulsion. As shown in the particular embodimentdepicted in FIG. 1, the photosensitive element 22 is shown in aspread-apart relationship (as, for example, during exposure) with animage-receiving element 24 having mounted thereon a rupturable container14 holding a processing composition. The imagereceiving element 24comprises a support and an imagereceiving layer 12. After exposure, theimage-receiving element 24 is brought into superposed relationship withphotosensitive element 22, rupturable container 14 is ruptured byapplication of suitable pressure, for example, by advancing between apair of rolls (not shown), and a layer of the liquid processingcomposition is spread between the superposed elements. The processingcomposition permeates the silver halide emulsion and developes a latentimage contained therein. Subsequent to exposure, the temporarily shifteddye developer is restored to its original spectral absorptioncharacteristics. In unexposed areas, the dye developer will transfer tothe superposed image-receiving element 24, to constitute thereon apositive dye image in terms of exposure, said image exhibiting thespectral absorption characteristics of the desired restored dyedeveloper. The image-receiving element 24 is separated from itssuperposed relationship with the photosensitive element 22 after atleast a portion of the dye developer has been transferred.

It should be noted that it is within the scope of the present inventionto form images which comprise mixtures of temporarily shifted dyedevelopers and non-shifted or restored dye developers. The restorationof the respective dye developers original spectral absorptioncharacteristics may be effected by reacting said dye developer with oneor more processing compositions, subsequent to photoexposure, but priorto, concurrently with or subsequently to photographic rocessing. Ifdesired, a transferred dye developer containing image-receiving elementmay be contacted with said processing compositions subsequent todissociation of said image-receiving element from its superposedrelationship to the photosensitive element. For example, a temporarilyshifted esterified dye developer containing image-receiving element, theester components of said dye developer being difficultly hydrolyzable,may be subjected to additional caustic hydrolysis by contact with asecond hydrolytic processing composition prior to or subsequent to theaforementioned dissociation to provide an increased quantity ofhydrolyzed dye developer therein. In the following examples, all partsare given by weight except where otherwise noted and all operationsinvolving light-sensitive materials are carried out in the absence ofactinic radiation. These examples are intended to be illustrative onlyof the synthesis and employment of temporarily shifted dye developerswherein, subsequent to photoexposure, at least a portion of saidtemporarily shifted dye developer is restored to the desired subtractivecolor absorption spectrum to provide a reversed positive transfer imageof the photographed subject and should not be considered as limiting theinvention in any way.

EXAMPLE 1 10 gm. of 2-(p-[B-(hydroquinonyl)-ethyl]-phenylazo)-4-methoxy-1-naphthol, the preparation of which is disclosed in theaforementioned copending US. application, Serial No. 612,045, and 10.5gm. of benzoquinone are re fluxed for 3.5 hours in 150 cc. of chloroformto provide 3 gm. of

4-methoxy-2- (p- ,8- (p'-quinonyl) -ethyl] phenylazo) -1-naphthol.

EXAMPLE 2 8 gm. of4-methoxy-2-(p-[B-(p-quinonyl)-ethyl]-phenylazo)-1-naphthol and 25 gm.of l-propen-2-ol acetate are dissolved in cc. of ethyl acetate. 2 dropsof concentrated sulfuric acid are added and the resultant solutionrefluxed for 2.5 hours. The solution is then filtered through sodiumbicarbonate and the filtrate is diluted with two volumes of hexane. Theproduct is crystallized at 5 C. and collected by filtration.

The resultant product:

OCH:

l-acetoxy-4-methoxy-2-(p[,8-(p'-quinonyl)-ethyl]-phenylazo)-naphthalene, exhibits a spectralabsorption curve which displays a k at 396 m in acetone; e=6,800-.

EXAMPLE 3 0.3 gm. of 1-acetoxy-4-methoxy-2-(p-[fi-(p'-quinonyl)ethyl]-phenylazo)-naphthalene is dissolved in 15 cc. of chloroform andreduced with 0.3 gm. of 2,5-xylohydroquinone.

The resultant product:

l-acetoxy 2 (p-[B-(hydroquinonyl)-ethyl]-phenylazo)4-methoxy-naphthalene is separated and purified by chromatographing onacetic acid washed alumina. The purified product exhibits a spectralabsorption curve which displays a A at 390 m in acetone; e=6,700.

EXAMPLE 4 5 gm. of 2-(p-[/8-(hydroquinonyl)-ethyl]-phenylazo)4-n-propoxy-1-naphthol, the preparation of which is disclosed in theaforementioned copending US. application Serial No. 612,045, and 6 gm.of benzoquinone are refluxed for 3.5 hours in 200 cc. of chloroform toprovide 3.3 gm. of

O-CsH 4-n-propoxy-2-(p-[B-(p'quinonyl) ethyl] phenylazo) l-naphthol.

' EXAMPLE 6 3.0 gm. (0.0062 mole) of 4-n-propoxy-2-(p-[fi-(p'-quinonyl)-ethyl]-p enylazo)-1-naphthol and 15 cc. of 1- propen-Z-olacetate are dissolved in 200 cc. of methylene chloride. drops ofconcentrated sulfuric acid are added and the resulting solution refluxedfor 2 hours. After cooling, the solution is poured into 200 cc. ofligroin, the product crystallized at approximately 5 C. for V 24 hoursand collected by filtration.

The resultant product:

l-acetoxy 4 n propoxy-2-(p-[fi-(p'-quinonyl)-ethyl]'phenylazo)-naphthalene, exhibits a spectral absorption curve whichdisplays a A at 396 m in acetone;

EXAMPLE 7 3, gm. of 1-acetoxy-4-n-propoxy-2-(p-[/3-(p'-quinony1)ethyl]-phenylazo)-naphthalene are dissolved in 50 cc. of

'ethyl acetate and reduced by refluxing the solution with 3 gm. of2,5-xylohydroquinone for 3 hours. After sub- 14 stantially completereaction, the solution is filtered and the product purified bychromatographing an acetic acid washed alumina.

The resultant product:

l-acetoxy 2 (p-[B-(hydroquinonyl)-ethyl]-phenylazo)4-n-propoxynaphthalene, exhibits a spectral absorption curve whichdisplays a A at 390 mu in acetone; 6:6,700.

EXAMPLE 8 1.3 gm. of 2-(p-[2',5'-dihydroxyphenoxy]-phenylazo)4-methoxy-1-naphthol, the preparation of which is disclosed in theaforementioned copending US. application Serial No. 680,403, and 1.3 gm.of benzoquinone are refluxed for 3.5 hours in 10 cc. of chloroform.After filtering the hot solution, the filtrate is diluted with an equalvolume of liquor to provide 1.0 gm. of the desired product:

0 OH H l 4-methoxy-2-(4-[p-quinonyloxy] phenylazo)-1-naphthol exhibitinga melting point at to 192 C.

EXAMPLE 9 1.0 gm. of4-methoxy-2-(p-[p'-quinonyloxyl]-phenylaz0)-1-naphthol and 3.5 cc. of1-propen-2-ol acetate is dissolved in 50 cc. of methylene chloride. 6drops of concentrated sulfuric acid are added to the solution. After theinitial reaction, the solution is warmed for 15 minutes and then pouredinto a separatory funnel, washed with Water and then washed with asaturated sodium bicarbonate solution. The resultant solution is driedover anhydrous magnesium sulfate. The solvents are removed in vacuo andthe residual oil,

OCHa

1 acetoxy 4 methoxy 2 (4' [p quinonyloxy]- phenylaZo)-naphthalene, isdissolved in 15 cc. of ethyl acetate.

EXAMPLE 10 The product of Example 9 is reduced by adding 0.5 gram of a10% palladium/carbon catalyst and treating with hydrogen under 1atmosphere pressure. After substantially complete reaction, the solventis removed by evaporation, and the product is stirred with 5 cc. ofmethylene chloride and separated by filtration.

15 The resultant product:

- i OH OC-OH l OH OCI-Ia l acetoxy 2 (p [2,5 dihydroxyphenoxy]phenylazo)-4-methoxy-naphthalene, exhibits a spectral absorption curvewhich displays a k at 409 m in acetone; 5:9,100 and a at 389 m inacetone; e=9,700.

Substitution of appropriate starting materials in the aforementionedexamples, such as substituting one or more of the previously enumeratedortho-hydroxy and/ or ortho,ortho'-dihyd-roxyazo dyes and/or one or moreof the previously enumerated acylating agents, provides additionalcompounds Within the previously stated generic formulae.

EXAMPLE 1 1 A photosensitive element is prepared by coating agelatin-coated film base with a solution comprising 3% of l acetoxy 2 (p[[3 (hydroquinonyl) ethyl] phenylazo)-4- methoxy-naphthalene (k 390 myin acetone; e=6,700) and 4% cellulose acetate hydrogen phthal atedissolved in a 50:50, by volume, solution of acetone andtetrahydrofuran. After this coating has dried, a silver iodobromideemulsion is applied thereon. This photosensitive element is exposed andprocessed by spreading an aqueous liquid processing compositioncomprising:

Percent Sodium oarboxyrnethyl cellulose 5.5 Sodium hydroxide 4.01-phenyl-3-pyrazolidone 1.2 2,5-bis-ethyleneirnino-hydroquinone 0.96-nitrobenzimidazole 0.12

between said photosensitive element and an image-receiving element assaid elements are brought into superposed relationship. Theimage-receiving element comprises a cellulose acetate-coated baryt apaper which has been coated with a 4% solution of N-methoxymethylpolyhexamethylene adipamide in ethanol. After an imbibition period ofapproximately 1 minute, the image-receiving element is separated andcontains a magenta positive dye image,2-(p-[ti-(hydroquinonyl)-ethyl]-phenylazo)- 4 methoxy 1 naphthol (k 529mu in acetone; e=19,800), of the photographed subject.

EXAMPLE 12 A photosensitive element is prepared, exposed and processed,according to the procedure of Example 11, wherein the image-receivingelement comprises a cellulose acetate-coated baryta paper which has beencoated with a mixture of 3% polyvinyl alcohol and 1% polyvinylpyrrolidone. After an imbibition period of approximately 1 minute, theimage-receiving element is separated and contains a magenta positive dyeimage, Z-(p-[fl-(hydroquinonyl) -ethyl] -phenylazo)-4-methoxy-1-naphthol, of the photographed subject.

EXAMPLE 13 A photosensitive element is prepared by coating agelatin-coated film base with a solution comprising 3% of 1 acetoxy 2 (p[/3 (hydroquinonyl) ethyl] phenylazo)-4-n-propoxy-naphthalene (A 390111,44 in acetone; -e=6,700) and 4% cellulose acetate hydrogen phthalatedissolved in a 50:50, by volume, solution of acetone andtetrahydrofuran. After this coating has dried, a silver iodobromideemulsion is applied thereon. This photosensitive element is exposed andprocessed by spreading an aqueous liquid processing compositioncomprising:

Percent Sodium carboxymethyl cellulose 5 .0 Sodium hydroxide 3.01-phenyl-3-pyrazolidone 1.2 2,5 -bis-ethyleneirnino-hydroquinone 0.96-nitrobenzimidazole 0.16

between said photosensitive element and an image-receiving element assaid elements are brought into superposed relationship. Theimage-receiving element was prepared as in Example 11. After animbibition period of approximately 1 minute, the image-receiving elementis separated and contains a magenta positive dye image,Z-(p-[B-(hydroquinonyl) ethyl] phenylazo) 4 n propoxy 1- naphthol (k 529m in acetone; e=19,800), of the photographed subject.

EXAMPLE 14 A photosensitive element is prepared by coating agelatin-coated film base with a solution comprising 3.5% of 1acetoxy-2-(p-[2,5'-dihydroxyphenoxy]-phenylazo)- 4-methoxy-naphthalene(a a at 409 m in acetone; e=9,l()0 and a a at 389 m in acetone;-s=9,700), and 4% cellulose acetate hydrogen phthalate dissolved in a50:50, by volume, solution of acetone and tetrahydrofuran. After thiscoating has dried, a silver iodobromide emulsion is applied thereon.This photosensitive element is exposed and processed by spreading anaqueous liquid processing composition comprising:

Percent Sodium carboxymethyl cellulose 4.5 Sodium hydroxide 2.0l-phenyl-3pyrazolidone 0.9 2,5 -bis-ethyleneimino-hydroquinone 0.46-nitrobenzimidazole 0.12

between said photosensitive element and an image-receiving element assaid elements are brought into superposed relationship. Theimage-receiving element was prepared as in Example 11. After animbibition period of approximately 1 minute, the image-receiving elementis separated and contains a magenta positive dye image,Z-(p-[2',5-dihydroxyphenoxy] pheny-lazo)-4-rnethoxy-1- naphthol, of thephotographed subject.

It is also contemplated to utilize in the preparation of monochromaticimages, a film structure wherein the photosensitive element is coatedover the image-receiving layer and the processing composition mustpermeate through the emulsion before reaching the image-receiving layer.A structure of this type is described, for example, in US. Patent No.2,661,293, issued to Edward H. Land on December 1, 1953, andparticularly with respect to FIG. 7 of said patent.

Multicolor images may be obtained using dye developers indiffusion-transfer reversal processes by several techniques. One suchtechnique contemplates the use of a photosensitive silver halide stratumcomprising at least two sets of selectively sensitized minutephotosensitive elements arranged in the form of a photosensitive screen.Transfer processes of this type are disclosed in the copending US.application of Howard G. Rogers, Serial No. 748,421 (now US. Patent No.2,983,606, issued May 9, 1961), and also in the copending US.application of Edwin H. Land, Serial No. 448,441, filed August 9, 1956(now US. Patent No. 2,968,554, issued January 17, 1961). In such anembodiment, each of the minute photosensitive elements has associatedtherewith an appropriate dye developer in or behind the silver halideemulsion portion. In general, a suitable photosensitive screen, preparedin accordance with the disclosures of the last-mentioned copendingapplications, comprises minute red-sensitized emulsion elements, minutegreen-sensitized emulsion elements and minute blue-sensitized emulsionelements arranged in side-by-side relationship in a screen acteristics.

17 pattern and having associated therewith, respectively, a cyan dyedeveloper, a magenta dye developer and a yellow dye developer.

Another process for obtaining multicolor transfer image utilizing dyedevelopers employ an integral multilayer photosensitive element such asis disclosed and claimed in the copending U.S. application of Edwin .H.

Land and Howard G. Rogers, Serial No. 565,135, wherein at least twoselectively sensitized photosensitive strata are superposed on a singlesupport and are processed, simultaneously and without separation, with asingle, common image-receiving layer. A suitable arrangement of thistype comprises a support carrying a red-sensitive silver halide emulsionstratum, a green-sensitive silver halide emulsion stratum and ablue-sensitive silver halide emulsion stratum, said emulsions havingassociated therewith, respectively, a cyan dye developer, a magenta dyedeveloper and a yellow dye developer. The dye developer may be utilizedin the silver halide emulsion layer, for example, in the form ofparticles, or it may be employed as a layer behind the appropriatesilver halide emulsion strata. Each set of silver halide emulsion andassociated dye developer strata may be separated from other sets bysuitable interlayers, for example, by a layer of gelatin and/ orpolyvinyl alcohol.

A multilayer photosensitive element of the type just described isillustrated in FIG. 2 of the accompanying drawings and is depictedduring processing. An exposed photosensitive element 60 comprises: asupport 58; a layer 54 containing a cyan dye developer and aredsensitive silver halide emulsion; a layer 50 of a magenta dyedeveloper exhibiting a temporarily shifted spectral absorption curve anda green-sensitive silver halide emulsion; a layer 46 containing a yellowdye developer and a blue-sensitive silver halide emulsion. As notedabove, each set of silver halide emulsion and associated dye developerstrata may be separated from other sets thereof by suitable interlayers(not shown), for example, by a layer of gelatin and/or polyvinylalcohol. In certain instances, it may be desirable to incorporate ayellow filter in front of the green-sensitive emulsion and such yellowfilter may be incorporated in an interlayer. However, where desirable, ayellow dye developer of the appropriate spectral characteristics andpresent in a state capable of functioning as a yellow filter may beemployed. In such instances, a separate yellow filter may be omitted.

Referring again to FIG. 2, a multilayer photosensitive element 60 isshown in processing relationship with an image-receiving element 62 anda layer 44 of a processing composition. The image-receiving element 62comprises a support 4-0 and an image-receiving layer 42. As noted inconnection with FIG. 1, the liquid processing composition is effectiveto initiate development of the latent image in the respective exposedsilver halide strata and also may etfect restoration of the respectivetemporarily shifted magenta dye developer to its original absorptionchar- After a suitable imbibition period, during which at least aportion of the dye developer associated with unexposed areas of each ofsaid emulsions is transferred to the superposed image-receiving element62, the latter element may be separated to reveal the positivemulticolor image.

It should be noted that it is within the scope of this invention toutilize, in multicolor diffusion-transfer reversal processes, one ormore of the requisite dye developers in the form of temporarily shifteddye developers. In certain instances, for example, it may be desirableto employ temporarily shifted dye developers in association with ared-sensitive and green-sensitive silver halide emulsion, together witha non-shifted dye developer associated with the blue-sensitive silverhalide emulsion.

A further technique for obtaining multicolor images employs a pluralityof photosensitive elements associated with an appropriate number ofimage receiving elements and adapted to be treated with one or moreliquid proc- 18 essingcompositions, the appropriate dye developers beingincorporated in the photosensitized elements. Examples of filmstructures of this type are disclosed in U.S. Patent No. 2,647,049,issued to Edwin H. Land on July 28, 1953.

The dye developers utilized in the processes of this invention may beincorporated in the photosensitive elements, for example in, on, orbehind the respective silver halide emulsion. The dye developer may, forexample, be in a coating or layer behind the silver halide emulsion andsuch a layer of dye developer may be applied by the use of a coatingsolution containing about 0.5 to 8%, byweight, of the respective dyedeveloper. When the temporarily shifted dye developers, set forth inExamples 1 and 2, were placed in a dye carrier layer behindthegreen-sensitive emulsion in an integral multilayer photosensitiveelement of the type described in connection with FIG. 2, sensitivity ofthe rearwardly positioned red-sensitive emulsion was extendedapproximately 30 m into the shorter wave lengths of the spectrum, thatis, the sensitivity of the red-sensitive emulsion was extended fromapproximately 640 m down to approximately 610 mu.

The liquid processing composition herein referred to comprises at leastan aqueous solution of an alkaline compound, for example, diethylamine,sodium hydroxide or sodium carbonate. If the liquid processingcomposition is to be applied to the emulsion by being spread thereon,preferably in a relatively thin uniform layer, it may also include aviscosity-increasing compound constituting a film-forming material ofthe type which, when said composition is spread and dried, forms arelatively firm and relatively stable film. A preferred film-formingmaterial is a high molecular weight polymer such as a polymeric,water-soluble ether which is inert to an alkaline solution such as, forexample, a hydroxyethyl cellulose or sodium carboxymethyl cellulose.Other film-forming materials or thickening agent-s whose ability toincrease viscosity is substantially unaffected if left in solution for along period of time may also be used. The film-forming material ispreferably contained in the processing composition in suitablequantities to impart to said composition a viscosity in excess of 1,000centipoises at a temperature of approximately 24 C. and preferably ofthe order of 1,000 to 200,000 centipoises at said temperature.Illustrations of suitable liquid processing compositions may be found inthe several patents and copending applications herein mentioned and alsoin examples herein given. Under certain circumstances, it may bedesirable to apply a liquid processing composition to the photosensitiveelement prior to exposure, in accordance with the technique described inthe copending U.S. application of Edwin H. Land, Serial No. 498,672,filed April 1, 1955 (now U.S. Patent No. 3,087,816 issued April 30,1963).

It will be noted that the liquid processing composition employed maycontain an auxiliary or accelerating developing agent, such asp-methylaminophenol, 2,4-diaminophenol, p-benzylaminophenol,hydroquinone, toluhydr-oquinone, phenylhydroquinone.4-rnethylphenylhydroquinone, etc. It is also contemplated to employ aplurality of auxiliary or accelerating developing agents, such as a3-pyrazolidone developing agent and a benzenoid developing agent, asdisclosed in U.S. Patent No. 3,039,869, issued June 19, 1962. Asexamples of suitable combinations of auxiliary developing agents,mention may be made of 1-phenyl-3-pyrazolidone in combination with pbenzylaminophenol and 1-phenyl-3-pyrazolidone in combination with2,5-bis-ethyleneimino-hydroquinone. Such auxiliary developing agents maybe employed in the liquid processing composition or they may beinitially incorporated, at least in part, in the silver halide emulsionstrata or the strata containing the dye developers. It may be noted thatat least a portion of the dye developer oxidized during development maybe oxidized and immobilized as a result of a reaction, e.g., anenergy-transfer reaction, with the oxidation product of an oxidizedauxiliary developing agent, the latter developing agent being oxidizedby the development of exposed silver halide. Such a reaction of oxidizeddeveloping agent with unoxidized dye developer would regenerate theauxiliary developing agent for further reaction with the exposed silverhalide.

In addition, development may be efiected in the pres ence of an oniumcompound, particularly a quaternary ammonium compound, in accordancewith the processes disclosed in the copending U.S. application of MiltonGreen and Howard G. Rogers, Serial No. 50,861, filed August 22, 1960(now U.S. Patent No. 3,057,905).

The dye developers are preferably selected for their ability to providecolors that are useful in carrying out subtractive color photography,i.e., cyan, magenta and yellow. It should be noted that it is within thescope of this invention to use mixtures of dye developers to obtain adesired color, e.=g., black. Thus it is to be understood that theexpression color as used herein is intended to include the use of aplurality of colors to obtain black, as well as the use of a singleblack dye developer.

In all products employed in the practice of this invention, it ispreferable to expose from the emulsion side. It is, therefore, desirableto hold the photosensitive element and the image-receiving elementtogether at one end thereof by suitable fastening means in such mannerthat the photosensitive element and the image-receiving ele ment may bespread apart from their superposed processing position during exposure.A camera apparatus suitable for processing film of the type justmentioned is provided by the Polaroid Land Camera, sold by PolaroidCorporation, Cambridge, Massachusetts, or similar camera structure such,for example, as the roll fihn type camera forming the subject matter ofU.S. Patent No. 2,435,717 or the film pack-type camera forming thesubject matter of U.S. Patent No. 2,991,702. Camera apparatus of thistype permits successive exposure of individual frames of thephotosensitive element from the emulsion side thereof as well asindividual processing of an exposed frame by bringing said exposed frameinto superposed relation with a predetermined portion of theimage-receiving element while drawing these portions of the filmassembly between a pair of pressure rollers which rupture a containerassociated therewith and effect the spreading of the processing liquidreleased by rupture of said container, between and in contact with theexposed photosensitive frame and the predetermined, registered area ofthe image-receiving element.

The nature and construction of rupturable containers such as that shownin FIGURE 1 is well understood in the art; see, for example, U.S. PatentNo. 2,543,181, issued to Edwin H. Land on February 27, 1951, and U.S.Patent No. 2,634,886, issued to Edwin H. Land on April 14, 1953.

The image-receiving element comprises an image-receiving layer of opaqueor transparent material which is liquid permeable and dyeable fromalkaline solutions and which has been illustrated for purposes ofsimplicity as comprising a single sheet of permeable material, forexample, paper. This element, however, may comprise a support upon whichat least one liquid-permeable and dyeable layer is mounted. The supportlayer may have a water-impermeable subcoat over which the stratum ofpermeable and dyeable material is applied. In certain instances, thedyeable layer may comprise a layer of liquid processing compositionwhich is adapted to remain adhered to the support layer upon stripping.

As examples of useful image-receiving materials, mention may be made ofnylon, e.g., N-methoxymethyl-polyhexamethylene adipamide, polyvinylalcohol, and gelatin, particularly polyvinyl alcohol or gelatincontaining a dye mordant such as poly-4-vinylpyridine, and othermaterials of a similar nature, as is well known in the art. The

20 image receiving element also may contain a development restrainer,e.g., l-phenyl-5-mercaptotetrazole, a disclosed in the copendingapplication of Howard G. Rogers and Harriet W. Lutes, Serial No. 50,849,filed August 22, 1960.

While a rupturable container, such as container 14 in FIGURE 1, providesa convenient means for spreading a liquid processing composition betweenlayers of a film unit whereby to permit the processing to be carried outwithin a camera apparatus, the practices of this invention may beotherwise effected. For example, a photosensitive element, afterexposure in suitable apparatus and while preventing further exposurethereafter to actinic light, may be removed from such apparatus andpermeated with the liquid processing composition as by coating thecomposition on said photosensitive element or otherwise wetting saidelement with the composition following which the permeated, exposedphotosensitive element, still without additional exposure to actiniclight, is brought into contact with the image-receiving element forimage formation in the manner heretofore described.

It is also to be understood that the invention may be successfullypracticed Without the use of a film-forming material in the liquidprocessing composition. As an illustration, a non-viscous liquidprocessing composition is particularly applicable with the processingtechnique last mentioned above and may be applied to the exposedphotosensitive element by imbibition or coating practices and may besimilarly applied to the image-receiving element before said elementsare brought into superposed relation or contact for carrying out thetransfer of nonirnmobilized color-providing substances.

It will be apparent that the relative proportions of the agents of thediffusion transfer processing composition may be altered to suit therequirements of the operator. Thus, it is within the scope of thisinvention to modify the herein described developing compositions by thesubstitution or addition of preservatives, alkalies, silver halidesolvents, etc., other than those specifically mentioned. When desirable,it is also contemplated to include, in the developing composition,components such as restrainers, accelerators, etc. Similarly, theconcentration of various components may be varied over a wide range and,when desirable, adaptable components may be dis posed in thephotosensitive element, prior to exposure, in a separate permeable layerof the photosensitive element and/ or in the photosensitive emulsion.

In all examples of this specification, percentages of components aregiven by weight unless otherwise indicated.

Throughout the specification the expression positive image has beenused. This expression should not be interpreted in a restrictive sensesince it is used primarily for purposes of illustration, in that itdefines the imag produced on the image-carrying layer as being reversed,in the positive-negative sense, with respect to the image in thephotosensitive element. As an example of an alternative meaning forpositive image, assume that the photosensitive element is exposed toactinic light through a negative transparency. In this case, the latentimag in the photosensitive element will be a positive and the imageproduced on the image-carrying layer will be a negative. The expressionpositive image is intended to cover such an image produced on theimage-carrying layer.

The dye developers of this invention may be used also in conventionalphotographic processes, such as tray or tank development of conventionalphotosensitive films, plates or papers to obtain black and white,monochromatic or toned prints or negatives. By way of example, adeveloper composition suitable for such use may comprise an aqueoussolution of approximately 1 to 2% of the dye developer, 1% sodiumhydroxide, 2% sodium sulfite and 0.05% potassium bromide. Afterdevelopment is completed, any unreacted dye developer is washed out ofthe photosensitive element, preferably with an alkaline washing mediumor other medium in which the unreacted dye developer is soluble. Theexpression toned is used to designate photographic images wherein thesilver is retained with the precipitated dye, whereas monochromatic" isintended to designate dye images free of silver.

Since certain changes may be made in the above product and processwithout departing from the scope of the invention herein involved, it isintended that all matter contained in the above description or shown inthe accompanying drawing shall be interpreted as illustrative and not ina limiting sense.

What is claimed is:

1. A process of forming transfer images in color which comprises thesteps of exposing a photosensitive element containing a silver halideemulsion and an azo dye which contains a dihydroxyphenyl sliver halidedeveloping radical and at least one group'selected from the groupconsisting of a hydrolyzable acylated hydroxyl group and a hydrolyzableacylated amino group in at least one of ortho and para positions to anazo group; permeating said photosensitive element with an aqueousalkaline solution; providing thereby solubilization of said dye,deacylation of said acylated group, by hydrolysis, and thereby anonreversible bathochromic shift of the spectral absorptioncharacteristics of said dye, and development of said exposed silverhalide emulsion; immobilizing said dye in developed areas of saidelement, as a result of development; forming thereby an imagewisedistribution of mobile dye, as a function of the point-to-point degreeof exposure of said emulsion; and transferring, by imbibition, at leasta portion of said mobile dye to a superposed image-receiving layer toprovide thereto a dye image.

2. A process of forming transfer images in color as defined in claim 1which comprises the steps of exposing a photosensitive elementcontaining a silver halide emulsion sensitive to a primary spectralsensitivity range and an associated dye, which dye is both a silverhalide developing agent and a complete preformed azo dye, said azo dyeselected from the group consisting of monoand disazo dyes having atleast one hydrolyzable group selected from the group consisting ofacylated hydroxyl and acylated amino groups in one of ortho and parapositions to an azo group and possessing major spectral absorption atwavelengths without the primary region of the spectrum to which theassociated silver halide emulsion is sensitive and spectral transmissionsubstantially complementary to said absorption; developing said exposedsilver halide emulsion; immobilizing said dye as a result ofdevelopment, in the developed areas of said element, as a function ofthe point-to-point degree of exposure of said emulsion; forming therebyan imagewise distribution of mobile dye; effecting, substantiallycontemporaneous with said development, hydrolysis of said hydrolyzablegroup to thereby provide a dye possessing major spectral absorptionwithin the spectral range to which the associated silver halide emulsionis sensitized; and transferring, by imbibition, at least a portion ofsaid imagewise distribution of dye to a superposed imagereceiving layerto provide thereto a dye image possessing major spectral absorptionwithin the spectral range to which the associated silver halide emulsionis sensitized and spectral transmission substantially complementary tosaid absorption.

3. A photographic product comprising a plurality of layers, at least oneof said layers comprising a silver halide emulsion, at least one of saidlayers containing an azo dye which contains a dihydroxyphenyl silverhalide developing radical and at least one group selected from the groupconsisting of a hydrolyzable acylated hydroxyl group and a hydrolyzableacylated amino group in at least one of ortho and para positions to anazo group.

4. A photographic product as defined in claim 3 wherein said silverhalide emulsion is sensitive to a primary spectral sensitivity range andsaid azo dye is both a silver halide developing agent and a completepreformed azo dye selected from the group consisting of monoand disazodyes having at least one hydrolyzable group selected from the groupconsisting of acylated hydroxyl and acylated amino groups in one ofortho and para positions to an azo group and possessing major spectralabsorption at wavelengths without the primary region of the spectrum towhich the associated silver halide emulsion is sensitive.

5. A photographic product as defined in claim 4 wherein said azo dyepossesses major spectral absorption at Wavelengths within said primaryregion of the spectrum subsequent to hydrolysis of said hydrolyzablegroup.

6. A process of forming transfer images in color which comprises thesteps of exposing a photosensitive element containing a silver halideemulsion and a dye selected from the group consisting of monoand disazodyes which contain a dihydroxyphenyl silver halide developing radicaland an acylated hydroxy group in ortho position to an azo group;permeating said photosensitive element with an aqueous alkalinesolution; providing thereby solubilization of said dye, deacylation ofsaid acylated hydroxyl group, by hydrolysis, and thereby anon-reversible bathochromic shift of the spectral absorptioncharacteristics of said dye, and development of said exposed silverhalide emulsion; immobilizing said dye in developed areas of saidelement, as a result of development; forming thereby an imagewisedistribution of mobile dye, as a function of the point-to-point degreeof exposure of said emulsion; and transferring, by imbibition, at leasta portion of said mobile dye to a superposed image-receiving layer toprovide thereto a positive dye image.

7. A process of forming transfer images in color as defined in claim 6,including the step of elfecting said development in the presence of anadditional, accelerating silver halide developing agent.

8. A process of forming transfer images in color as defined in claim 6,wherein said dye is l-acetoxy-Z-(p- [B-(hydroquinonyl) -ethyl]-phenylazo) -4 methoxy-naphthalene.

9. A process of forming transfer images in color as defined in claim 6,wherein said dye is l-acetoxy-Z-(p-[fl- (hydroquinonyl) ethyl]phenylazo) 4 n propoxynaphthalene.

13. A process of forming transfer images in color as defined in claim 6,wherein said dye is l-acetoxy-2-(p-[2',5'-dihydroxyphenoxy]-phenylazo)-4 methoxynaphalene.

11. A photographic product comprising a plurality of layers, at leastone of said layers comprising a silver halide emulsion, at least one ofsaid layers containing a dye selected from the group consisting ofmonoand disazo dyes which contain a dihydroxyphenyl silver halideeveloping radical and an acylated hydroxy group in ortho position to anazo group.

12. A photographic product as defined in claim 11, wherein said dye isdisposed in said silver halide emulsion.

13. A process of forming transfer images in color which comprises thesteps of exposing a photosensitive element containing a silver halideemulsion and a dye selected from the group consisting of monoand disazodyes which contain not less than one and not more than two groupsselected from the groups represented by the formulae:

wherein each R represents a lower alkyl group; said dyes furthercharacterized in that they contain not less than one and not more thantwo dihydroxyphenyl silver halide developing radicals; permeating saidphotosensitive element with an aqueous alkaline processing composition,effecting thereby solubilization of said dye and deacylation of saidgroups, by hydrolysis, to provide hydroxyl groups and thereby a dyeselected from the group consisting of orthohydroxyazo andorth0,ortho'-dihydroxyazo monoand disazo dyes which contain not lessthan one and not more than two dihydroxyphenyl silver halide developingradicals, thereby providing a nonreversible bathochromic shift of thespectral absorption characteristics of said dye, and development of saidexposed silver halide emulsion; immobilizing said dye as a result ofdevelopment of the exposed areas of said emulsion and thereby forming animagewise distribution of mobile dye, as a func tion of thepoint-to-point degree of exposure of said emulsion; and transferring, byimbibition, at least a portion of said imagewise distribution of dye toa superposed image-receiving layer to provide thereon a positive dyeimage.

14. A photographic product which comprises a plurality of layers, atleast one of said layers comprising a silver halide emulsion, at leastone of said layers containing a dye selected from the group consistingof monoand disazo dyes which contain not less than one and not more thantwo groups selected from the groups represented by the formulae:

References Cited by the Examiner UNITED STATES PATENTS 11/1958 WilliamsRogers 96-29 NORMAN G. TORCHIN, Primary Examiner.

I. T. BROWN, Assistant Examiner.

UNITED STATES PATENT OFFICE CERTIFICATE. OF CORRECTION Patent No 3,307,947 March 7 1967 Elbert M. Ldel s on et al It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

Column 1*, line 64, for "lengths of" read lengths to column 3, line 23,after "excluding" insert oxidized column 7 line 36 for "ortho ortho readortho, ortho column 8, line 10, for "catcheol" read catechol lines 31and 41, for "1954", each occurrence read 1964 line 43, for"4methoxynaphtho l -read 4-methoxy-l-naphthol column 17 line 5 for "age"read ages same line 5 for "employ" read employs column 21 line 18 for"sliver" read silver Signed and sealed this 24th day of September 1968.

(SEAL) Attest: H

EDWARD M. FLETCHER,JR. EDWARD J. BRENNER Attesting Officer Commissionerof Patents

1. A PROCESS OF FORMING IMAGES IN COLOR WHICH COMPRISES THE STEPS OFEXPOSING A PHOTOSENSITIVE ELEMENT CONTAINING A SILVER HALIDE EMULSIONAND AN AZO DYE WHICH CONTAINS A DIHYDROXYPHENYL SILVER HALIDE DEVELOPINGRADICAL AND AT LEAST ONE GROUP SELECTED FROM THE GROUP CONSISTING OF AHYDROLYZABLE HYDROXYL GROUP AND A HYDROLYZABLE ACYLATED AMINO GROUP INAT LEAST ONE OF ORTHO AND PARA POSITIONS TO AN AZO GROUP; PERMEATINGSAID PHOTOSENSITIVE ELEMENT WITH AN AQUEOUS ALKALINE SOLUTION; PROVIDINGTHEREBY SOLUBILIZATION OF SAID DYE, DEACYLATION OF SAID ACYLATED GROUP,BY HYDROLYSIS, AND THEREBY A NONREVERSIBLE BATHOCHROMIC SHIFT OF THESPECTRAL ABSORPTION CHARACTERISTICS OF SAID DYE, AND DEVELOPMENT OF SAIDEXPOSED SILVER HALIDE EMULSION; IMMOBILIZING SAID DYE IN DEVELOPED AREASOF SAID ELEMENT, AS A RESULT OF DEVELOPMENT; FORMING THEREBY ANIMAGEWISE DISTRIBUTION OF MOBILE DYE, AS A FUNCTION OF THEPOINT-TO-POINT DEGREE OF EXPOSURE OF SAID EMULSION; AND TRANSFERRING, BYIMBIBITION, AT LEAST A PORTION OF SAID MOBILE DYE TO A SUPERPOSEDIMAGE-RECEIVING LAYER TO PROVIDE THERETO A DYE IMAGE.